A 4-year-old girl developed a space-occupying lesion in the bladder. This w
as demonstrated by US after resection of a huge ureterocoele and bilateral
re-implantation of ureters at 3 months of age and after three episodes of u
rinary tract infection. The mass developed outside the field of surgery and
was removed endoscopically. Histology revealed a nephrogenic adenoma. US f
indings have not been emphasised previously. US should be useful in the det
ection of such lesions and for surveillance of recurrence.